While you are correct that Section 508 is specific to U.S. Federal Government Web Sites, you missed the point.
The American's With Disabilities Act of 1973 has been amended to include non-Government web sites.
I admit that I copied from the site I support.
So, here is the longer version of compliance requirement per the U.S. Congress.
S.3304 as amended by S. 3828
One Hundred Eleventh Congress
United States of America
AT THE SECOND SESSION
Begun and held at the City of Washington on Tuesday,
the fifth day of January, two thousand and ten
TITLE I--COMMUNICATIONS ACCESS SEC. 101. DEFINITIONS.
Section 3 of the Communications Act of 1934 (47 U.S.C. 153) is amended--
(1) by adding at the end the following new paragraphs:
`(53) ADVANCED COMMUNICATIONS SERVICES- The term `advanced communications services' means--
`(A) interconnected VoIP service;
`(B) non-interconnected VoIP service;
`(C) electronic messaging service; and
`(D) interoperable video conferencing service.
`(54) CONSUMER GENERATED MEDIA- The term `consumer generated media' means content created and made available by consumers to online websites and services on the Internet, including video, audio, and multimedia content.
`(55) DISABILITY- The term `disability' has the meaning given such term under section 3 of the Americans with Disabilities Act of 1990 (42 U.S.C. 12102).
The act goes on with more legalize...I can bore you more details if you so feel the need?
- Bottom Line, since the site is being redone, it should be Disability Friendly within reasonable accommodation.
If ISC2.org does not make the regular site Disability Friendly, why would someone with disabilities ever want to purchase training on the site?
Why make persons with disabilities feel excluded?
Why does it have to be legislated to do the right thing? There is an ethical obligation to not exclude any member that is in good standing. The U.S. Federal Government had to mandate it for Federal Web Sites (Section 508) and then because the public sector did not follow, 11 years later they enacted 21st Century Communications and Video Accessibility Act of 2010 (CVAA)
Just in case anyone is interested in their country's regulations https://www.w3.org/WAI/policies/ - has a lot of useful information.